1. Field of the Invention
This invention relates to secure data communication and more specifically to a system and method for distributing secure digital information using a tamper-respondent device.
2. Description of the Relevant Art
Security issues have become a major concern in the area of digital communication. In order to address security concerns, the use of cryptography, digital certification, and digital signatures has been increasing in all areas of digital communication, including data transfers across networks, access to secure email servers and web servers, etc. Communication protocols involving the exchange of one or more encryption keys or other security information are becoming more and more common.
More and more of the devices exchanging information are relatively small computing devices, such as phones, PDAs, and other wireless, handheld devices. For these devices, conventional public-key cryptography systems (RSA, DH, DSA, etc.) may be impractical for small devices, in part because they involve the use of very large keys (e.g., 1024 bits), which may be cumbersome for a user to enter using the conventional input/output interfaces on these devices.
An alternate approach is to use a symmetric-key system. However, with symmetric-key systems, secure distribution of keys may be problematic. There is often not end-to-end security between users of a symmetric-key system. That is, there may be several security domain borders, at which the information may need to be decrypted and re-encrypted along the way. If one or more nodes along the path are compromised, the security of the entire network may be jeopardized. Another solution is to use public key encryption, such as encryption based on Elliptic Curve Cryptography (ECC). In public key encryption systems, even if the public key becomes known, a user may not be granted access to secure information until they enter a user-specific private key. In these systems, private keys are generated from the public key using a particular mathematical algorithm. Key generation may be performed on the small computing devices described above, but conventional small devices may not adequately protect the algorithm and authorization codes for generating keys from tampering and access by unauthorized users.